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| Titel |
Megalake Chad impact on climate and vegetation during the late Pliocene and the mid-Holocene |
| VerfasserIn |
C. Contoux, A. Jost, G. Ramstein, P. Sepulchre, G. Krinner, M. Schuster |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1814-9324
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| Digitales Dokument |
URL |
| Erschienen |
In: Climate of the Past ; 9, no. 4 ; Nr. 9, no. 4 (2013-07-05), S.1417-1430 |
| Datensatznummer |
250018083
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| Publikation (Nr.) |
 copernicus.org/cp-9-1417-2013.pdf |
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| Zusammenfassung |
| Given the growing evidence for megalakes in the geological record,
assessing their impact on climate and vegetation is important for the
validation of palaeoclimate simulations and therefore the accuracy of
model–data comparison in lacustrine environments. Megalake Chad (MLC)
occurrences are documented not only for the mid-Holocene but also for the
Mio-Pliocene (Schuster et al., 2009). At this time, the surface covered by water
would have reached up to ~350 000 km2 (Ghienne et al., 2002;
Schuster et al., 2005; Leblanc et al., 2006), making it an important
evaporation source, possibly modifying climate and vegetation in
the Chad Basin. We investigated the impact of such a giant continental
water area in two different climatic backgrounds within the
Paleoclimate Model Intercomparison Project phase 3 (PMIP3): the late
Pliocene (3.3 to 3 Ma, i.e. the mid-Piacenzian warm period) and the
mid-Holocene (6 kyr BP). In all simulations including MLC,
precipitation is drastically reduced above the lake surface because
deep convection is inhibited by overlying colder air. Meanwhile,
convective activity is enhanced around MLC because of the wind increase generated by the flat surface of the
megalake, transporting colder and moister air towards the eastern
shore of the lake. The effect of MLC on precipitation and temperature
is not sufficient to widely impact vegetation patterns. Nevertheless,
tropical savanna is present in the Chad Basin in all climatic
configurations, even without MLC presence, showing that the
climate itself is the driver of favourable environments for
sustainable hominid habitats. |
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